I also assume that their bottlenoses are from Taiji, since Black Sea bottlenoses are illegal to capture, and Japan is nearby.
Bottlenoses for Novosibirsk zoo dolphinarium (in contsruction) are also from Taiji.
Nobody bothers to breed and raise enough dolphins in captivity until this source is functioning. And many of calves that are born in Russia & Ukraine have died early.

Considering the new photos appeared at Facebook (as you have already found out), I must admit that I made error in scaling (though the video was too short to depict the whole tank).
The oceanarium's officials say that there are 2 temporary tanks 25 m diameter and 8 m deep, connected by gate, with combined volume of 8000 cubic meters (and claiming that the standards are 2000 cubic meters per orca, is it true?!)
The orcas would be moved to public exhibit in December, where will be 3 exhibit tanks and quarantine zones, total volume is said to be 30000 cubic meters.
Main tank measurements are 50x30x14 (which is already 21000 cubic meters, looks like smaller tanks are really small or the officials lie).

Latest deaths:
15th October, 2015: beluga
19th January 2016: bottlenose (spontaneous allergic reaction to food, stomach spasm, Pseudomonas was found in skin & blood samples of dead and living specimens)
15th April 2016: one of belugas removed the drain cover and stuck there